7-49 Have Fun with Numbers (20分)
Notice that the number 123456789 is a 9-digit number consisting exactly the numbers from 1 to 9, with no duplication. Double it we will obtain 246913578, which happens to be another 9-digit number consisting exactly the numbers from 1 to 9, only in a different permutation. Check to see the result if we double it again!
Now you are suppose to check if there are more numbers with this property. That is, double a given number with k digits, you are to tell if the resulting number consists of only a permutation of the digits in the original number.
Input Specification:
Each input contains one test case. Each case contains one positive integer with no more than 20 digits.
Output Specification:
For each test case, first print in a line "Yes" if doubling the input number gives a number that consists of only a permutation of the digits in the original number, or "No" if not. Then in the next line, print the doubled number.
Sample Input:
1234567899
Sample Output:
Yes
2469135798
这题是一个典型的大数相乘 用了哈希来记录个位数出现次数。
#include<stdio.h>
#include<string.h>
#define N 23
int main()
{
char s[N];
int c=0;
int a[N];
int b[10];
int d[10];
memset(a,0,N*sizeof(int));
memset(b,0,10*sizeof(int));
memset(d,0,10*sizeof(int));
scanf("%s",s);
int i;
int len=strlen(s);
for(i=0;s[i]!='\0';i++)
a[i]=s[len-i-1]-'0';
for(i=0;i<len;i++)
{
b[a[i]]++;
}
for(i=0;i<len;i++)
{
a[i]=a[i]*2+c;
c=a[i]/10;
a[i]=a[i]%10;
}
if(c!=0)
{
a[i]+=c;
len+=1;
}
for(i=0;i<len;i++)
d[a[i]]++;
int flag=1;
for(i=0;i<10;i++)
{
if(d[i]!=b[i])
flag=0;
}
if(flag)
{
printf("Yes\n");
}
else
printf("No\n");
for(i=len-1;i>=0;i--)
printf("%d",a[i]);
printf("\n");
return 0;
}

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